High Ductility and Toughness of a Micro-duplex Medium-Mn Steel in a Large Temperature Range from -196 °C to 200 °C

Si-lian Chen, Jun Hu, Xiaodan Zhang, Han Dong, Wen-quan Cao

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A medium-Mn steel (0.2C5Mn) was processed by intercritical annealing at different temperatures (625 degrees C and 650 degrees C). An ultrafine-grained micro-duplex structure consisting of alternating austenite and ferrite laths was developed by austenite reverse transformation (ART) during intercritical annealing after forging and hot rolling. Ultrahigh ductility with a total elongation higher than 30% was achieved in the temperature range from - 196 degrees C to 200 degrees C and high impact toughness no less than 200 J at - 40 degrees C was obtained. Based on the analysis of microstructure and mechanical properties, it was found that the enhanced ductility was determined by the phase transformation effect 'of austenite (TRIP effect), while the delayed ductile to brittle transition was controlled by austenite stability.
Original languageEnglish
JournalJournal of Iron and Steel Research International
Issue number12
Pages (from-to)1126-1130
Publication statusPublished - 2015


  • High strength
  • High ductility
  • Intercritical annealing
  • Medium-Mn steel
  • Ultrafine grain size

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